Type casting tags to compare in expression binding

Ignition
1

Hello,

I have a tag (let's say called A) which contains a Short number.

I would like to use this tag to run the following code:

if (TagA = 16)
Return TagB
else
Return TagC

I am doing this in the Path property using expression binding as:

if (ToInteger({Root Container.TagPath}+"/Metering/TAP_POSITION")=16,
"[default]Bluestone/86B1/OP_ST 1",
"[default]Bluestone/86B1/OP_ST 2")

However, return statment is always TAG B. It does not return TAG C when TAG A is not 16.

Is anyone able to advise what I am doing wrong?

Thank you,
Ethan

2

See this for properly formatting code:

this is not doing what you think it is doing. You are trying to convert a string to an integer.

{Root Container.TagPath} will resolve to some string path, which will then concatenate to the other string.

Essentially your expression looks like this:

if(toInteger("path/to/tagA" + "/Metering/TAP_POSITION") = 16,"[default]Bluestone/86B1/OP_ST 1","[defalut]Blueston/86B1/OP_ST 2")

Instead, create a custom property on the window, perhaps the Root Container, and use an indirect tag binding to get the actual value of TagA. Same thing for TagB, and Tag C if what you want is the value of the tags and not the paths.

Then use the expression like this:

if(toInteger({Tag.A.Property}) = 16, {Tag.B.Property},{Tag.C.Property})

Honestly, there might be a better way, but I don't know exactly what you end goal is here. Also, since TagA is a short and it can hold the value 16, there is no need for it to be converted to an integer. So really the toInteger() expression is unneeded.

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3

Hey lrose,

Thank you very much for the help. I implemented you suggestion and this worked.
For my understanding, why is it that when I concatenate a string (which is a path of a tag containing a Short) and try to type cast it to an INT, why does it try to convert the string instead of the value contained at the string path?

Thanks again.

4

It doesn't automatically resolve a string to a tag path. To it, a string is just a string. You have to tell it to resolve the string to a tag. There are other ways to do it but this way is the best practice.

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